1. Field of the Invention
The present invention is related to a V-shaped block providing a V-shaped groove, in which single core or multiple core optical fibers are accommodated and anchored for positioning, used in a high strength fusing splice method.
2. Description of the Related Art
The V-shaped groove block is used in fusion splice and butt splice of optical fibers, and is most commonly used as a positioning groove for optical fibers.
A high strength fusion splice method for an optical fiber using a V-shaped groove block widely employed conventionally will be explained using FIG. 3xcx9cFIG. 5. Moreover, high strength fusion splice denotes a splice whose fusion part is difficult to break. FIG. 3 is a planar drawing for explaining the conventional high strength fusion splice method, FIG. 4 is a side view drawing, and FIG. 5 is a cross-sectional drawing along the line Cxe2x80x94C in FIG. 4. In addition, in the drawings, reference numeral 10 is a V-shaped groove provided in the V-shaped groove block, 12 is the V-shaped groove block, 20 is the optical fiber core wire, 22 is the covered part, 24 is the naked optical fiber made of glass, for example, and 30 is an electrode.
Conventionally, in the high strength fusion splice of optical fibers, first, the covered part 22 of the optical fiber core wire 20 is mounted on the V-shaped groove 10 of the V-shaped groove block 12 so as not to damage the naked optical fiber 24, and the optical fiber core wire 20 is grasped by a clamp (not shown). Next, the clamp is moved, the covered part 22 slides into the V-shaped groove 10, and the ends of the two naked optical fibers 24, 24 to be fusion connected are brought together. Next, the ends of the naked optical fibers 24, 24 are maintained opposite each other, the ends are fused by an aerial discharge, and they are integrally connected.
However, there are the following problems in the high strength fusion splice method wherein the optical fiber core wire 20 having a covered part 22 is mounted on the V-shaped groove 10.
1. The surface of the V-shaped groove 10 is made of ceramic, etc., and the covered part 22 is formed by a heat resistant resin, etc. Therefore, because the sliding resistance (friction coefficient) between the covered part 22 and the V-shaped groove 10 surface is high, the optical fiber core wire 20 may be dislocated. In particular, when fixed polarization optical fibers are in the high strength fusion splice, in order to align the polarization faces, it is necessary to rotate the optical fiber core wires 20. Due to this rotation, separation and curl of the covered part 22 occurs, and frequently the optical fiber core wire 20 becomes dislocated in the V-shaped groove 10. Because of this, it becomes difficult to move the optical fiber core wire 20 to a pre-determined position by sliding it in the V-shaped groove 10. In order to resolve this problem, the optical fiber core wire 20 anchored therein must moved by advancing and retracting the V-shaped groove block 12 itself However, this type of apparatus is large and complicated, and in addition, takes time for assembly and adjustment, and has a high cost.
2. Because of variation in the diameter of the covered part 22, variation occurs in the image observation position. Due to this, there is the concern that it is necessary to decrease the observation magnification, and as a result, the image processing resolution decreases, that is, the precision of the splice loss estimation is caused to decrease. In particular, in the case of the high strength fusion splice of fixed polarization optical fibers, when trying to define the polarization face, even though image processing is carried out, because dislocation is large, there is the concern that the naked optical fiber is prone to become separated from the screen.
In addition, in a conventional widely-used method of fusing a naked optical fiber 24 not having a covered part 22, there is the following drawback.
3. As explained in the above 1, the face of the V-shaped groove 10 is formed of ceramic, etc. Because of this, if the naked optical fiber 24 is scratched by the V-shaped groove 10, the side face of the naked optical fiber 24 will be damaged, a crack develop, and this can easily lead to a break due to this crack developing.
In consideration of the above matter, an object of the invention of the present application is to provide a V-shaped groove block for an optical fiber that resolves the above-described problems.
The V-shaped groove block for optical fibers of the present invention that positions by aligning the axes of the naked optical fibers is characterized in that a thin layer being formed comprising a material that does not damage the naked optical fiber even when the naked optical fiber slides thereon, is provided on a surface of a V-shaped groove.
In the V-shaped groove block for an optical fiber of the present invention, because the naked optical fiber is positioned by being advanced and retracted along the V-shaped groove, it is not necessary to move the V-shaped groove block. Therefore, the structure of the apparatus is simplified, and the assembly and adjustment, etc., are simple.
According to the V-shaped groove block for an optical fiber of the present invention, even if the naked optical fiber is mounted directly on the thin layer and advanced and retracted, there is no damage to the naked optical fiber. Due to this, it is possible to prevent cracks in the naked optical fiber and these from developing into breaks. Therefore, a high strength fusion splice becomes possible.
In addition, in the V-shaped groove block for an optical fiber of the present invention, because a naked optical fiber not having a covered part is mounted directly, it is possible to prevent variation in the image observation position that is caused by the variation in the diameter of the covered part. Therefore, it is possible to prevent lowering of the precision of the splice loss estimation.
In particular, in the case of connecting fixed polarization fibers, this naked optical fiber must be turned in the V-shaped groove, and thereby the above various problems are caused. However, these can be resolved by using the V-shaped groove block for optical fiber of the present invention.
Furthermore, the V-shaped groove block for an optical fiber of the present invention has the advantage that the optical fibers are not damaged even in the case that the optical fiber are anchored by the V-shaped groove being in permanent contact with the surface of the optical fiber, even in cases other than temporary anchoring of the optical fiber, as in butt splice.
Moreover, in this Specification, a V-shaped groove block denotes a platform on which a positioning groove is formed, but the cross-section thereof need not be a v-shape, and a U-shape or other shape is possible. In addition, the V-shaped groove block of the present invention can be used of course for connecting single core optical fibers, but can also be used to connect multiple core optical fibers.